McCoy ran his first full practice as Chargers coach with nearly 90 players present for the start of the team’s organized team activities (OTAs). The morning session saw a pair of Chargers veterans work with the starters while at a new position.

“The numbers were down, obviously, in those two camps,” McCoy said. “It’s nice to get everyone ... together for the first time and teach them the way we want to do it every day moving forward.”

Marcus Gilchrist has been taking reps at strong safety this offseason.

The experiment continued Monday.

The defensive back, who played some safety at Clemson, worked opposite Eric Weddle. Gilchrist primarily has been a cornerback since being drafted in 2011.

In three of four spots, the San Diego secondary could have a new starter.

Derek Cox replaces free agent Quentin Jammer at left corner. Shareece Wright is working with the ones on the right, where Antoine Cason started the past three years. And then there is Gilchrist, replacing free agent Atari Bigby.

“From a young age, my dad always told me if you’re going to play DB, you should play any position,” Gilchrist said. “I’ve always looked at it from that aspect, being able to be versatile enough to play corner, nickel and safety.”

In offseason turnover, the Chargers’ offensive line is the only position group that rivals the secondary.

Ex-right tackle Jeromey Clary worked with the starters Monday at right guard. King Dunlap was at left tackle, Chad Rinehart was at left guard and rookie D.J. Fluker played right tackle, leaving center Nick Hardwick as the only Chargers offensive lineman returning to the position in which he started last year.

Here in May, most spots on the depth chart are subject to change. That applies to the line’s left side.

The Chargers could add a free agent tackle, moving the versatile Dunlap into a reserve role. Left guard Johnnie Troutman, a 2012 fifth-round pick, worked with the second-team offense Monday and, despite not having Rinehart’s experience or familiarity with line coach Joe D’Alessandris, could push for the spot in training camp.

New visitor

Winston Justice is not a prototypical left tackle, but he is a veteran tackle.

That experience has caught the Chargers’ interest.

Justice was in San Diego on Monday for an official visit with the team. The eighth-year veteran has made 43 career starts, including 12 last season for the Colts.

All dozen came on the right side, Justice’s more natural position. Fluker appears entrenched as the Chargers’ starter there, so there is some question about where exactly Justice, 28, would fit.

San Diego is actively looking to add an experienced left tackle.

It hosted free agent Max Starks last week and remains interested in the former Steelers lineman. He projects as the starter if he does sign.

Testing

Blank blue books and Scantrons are still in Berkeley.

So, a third of the Chargers’ draft class must be, too.

Wide receiver Keenan Allen, a third-round pick, and cornerback Steve Williams, a fifth, were forced to miss the start of OTAs. Their absence is in accordance to an NFL rule that prohibits players who haven’t graduated from attending a team’s OTAs or voluntary workouts before final exams are complete.

At Cal, finals run through Friday, so Allen and Williams must wait before rejoining their team. Williams is scheduled to fly back into San Diego on Sunday.

Some undrafted rookies were absent Monday, too.

Defensive end Brandon Moore is at Texas, where final examinations wrap up today. Finals also conclude this week for quarterback Mike Hermann at the Rensselaer Polytechnic Institute.

Nuts ’n’ Bolts

Strong safety Brandon Taylor and inside linebacker D.J. Smith have yet to begin practicing this offseason. Both are coming off an ACL surgery, putting their availability for the July start of training camp in question.

• Manti Te’o, who spoke to reporters on Friday, was not made available Monday. He did receive a positive review from veterans with linebacker Donald Butler calling the rookie a “high-energy guy who likes to learn. Asking a lot of questions. Always trying to get better. That’s all we can ask for.”